Objectives: Extra virgin olive oil (EVOO) is a key component of the Mediterranean diet and seems to account for the protective effect against cardiovascular disease. However, the underlying mechanism is still elusive.
Design: We tested the effect of extra virgin olive oil, added to Mediterranean-type meal, on post-prandial glycemic and lipid profile.
Subjects: Post-prandial glycemic and lipid profile were investigated in 25 healthy subjects who were randomly allocated in a cross-over design to a Mediterranean-type meal added with or without 10 g extra virgin olive oil (first study), or Mediterranean-type meal with extra virgin olive oil (10 g) or corn oil (10 g; second study). Glycemic profile, which included glucose, insulin, dipeptidyl-peptidase-4 (DPP-4) protein and activity, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), and lipid profile, which included, low-density lipoprotein (LDL) cholesterol (LDL-C), oxidized LDL (ox-LDL), triglycerides and high-density lipoprotein (HDL) cholesterol (HDL-C), were analyzed before and 2 h after the meal.
Results: In the first study, 2 h after meal, subjects who assumed a meal with extra virgin olive oil had significantly lower blood glucose (P<0.001), DPP-4 protein (P<0.001) and activity (P<0.001), LDL-C (P<0.001) and ox-LDL (P<0.001) and higher insulin (P<0.05), GLP-1 (P<0.001) and GIP (P<0.05) compared with those without extra virgin olive oil. The second study showed that compared with corn oil, extra virgin olive oil improved both glycemic and lipid profile. Thus, a significantly smaller increase of glucose (P<0.05), DPP4 protein (P<0.001) and activity (P<0.05) and higher increase of insulin (P<0.001) and GLP-1 (P<0.001) were observed. Furthermore, compared with corn oil, EVOO showed a significantly less increase of LDL-C (P<0.05) and ox-LDL (P<0.001).
Conclusions: We report for the first time that extra virgin olive oil improves post-prandial glucose and LDL-C, an effect that may account for the antiatherosclerotic effect of the Mediterranean diet.